Why Do Diamond Tables Bank Shorter?

[Patrick Johnson]

thanks for the explanation of your username
what a beautiful table and from the look of that room your house...
aiming at 2 is not that short compared to most gc's 1 or 2
i have never had to aim past 2 on the gold crowns i have played on
thanks again for the reply

I hope you guys are all talking about shooting the 3-railer without side spin - otherwise who knows how much your aim depends on the amount of spin?

On my usual practice table (GC with clean, middle-aged 860) I aim without side spin just past the middle diamond between the side and corner pockets (on top of the rail).

pj
chgo

 

[oldschool1478]

I hope you guys are all talking about shooting the 3-railer without side spin - otherwise who knows how much your aim depends on the amount of spin?

On my usual practice table (GC with clean, middle-aged 860) I aim without side spin just past the middle diamond between the side and corner pockets (on top of the rail).

pj
chgo

Patrick, that's exactly how I aim the shot on my Diamond, when shooting the shot at pocket speed. If I need to hit it firm, I aim directly at the middle diamond. Middle-aged 760

 

[Patrick Johnson]

Patrick, that's exactly how I aim the shot on my Diamond, when shooting the shot at pocket speed. If I need to hit it firm, I aim directly at the middle diamond. Middle-aged 760

Interesting - just the kind of info I'm looking for. Thanks.

BTW, when I said "past" the middle diamond, I meant toward the corner.

pj
chgo

 

[beatle]

a proper 3 cushion shot would be with no english medium speed just above center ball.

hit the first diamond past the side pocket which is the third diamond up towards you from the back pocket. the cueball should then come off the third rail at the second diamond up and go into the pocket across from you every time without a miss..

when you start using running english on those shots that affects greatly and with your speed on where you have to hit to get it into the pocket. so then there is no way to use that as a guide on where to hit or how your rails play.

 

[Patrick Johnson]

a proper 3 cushion shot would be with no english medium speed just above center ball.

That's how I hit 'em, when possible.

hit the first diamond past the side pocket which is the third diamond up towards you from the back pocket. the cueball should then come off the third rail at the second diamond up and go into the pocket across from you every time without a miss..

By "should" do you mean on a Diamond table with new cloth? I think this result is highly dependent on conditions (rail type, cloth/ball cleanliness, humidity, etc.).

when you start using running english on those shots that affects greatly and with your speed on where you have to hit to get it into the pocket. so then there is no way to use that as a guide on where to hit or how your rails play.

Yes, that was my caveat too. Gotta eliminate/control the variables to get comparable results.

pj
chgo

 

[oldschool1478]

"hit the first diamond past the side pocket which is the third diamond up towards you from the back pocket. the cueball should then come off the third rail at the second diamond up and go into the pocket across from you every time without a miss.."

Shooting thru that diamond also works on my Diamond table with a just cleaned and polished cue ball.

After handling and it's picked up some chalk etc. it begins to shorten up.

 

[beatle]

thats how a table should do it. the variables of course change just where you have to hit the rail. some tables and equipment make you move a diamond.

you want to come off that third rail at the second diamond generally.

that is a shot needed before you play anyone for money on a strange table.

and also mirror shots where you see whether the angle of incidence equals the angle of reflection and if not, as well as the difference in how it lengthens and shortens with speed and english.

 

[LSJohn]

Patrick, that's exactly how I aim the shot on my Diamond, when shooting the shot at pocket speed. If I need to hit it firm, I aim directly at the middle diamond. Middle-aged 760

Am I right that you aim shorter if you plan to hit harder?

 

[lll]

I live in an old (1940) wood frame schoolhouse.
The address is 1478.


I shoot the three rail aiming at the second diamond past the side, or and inch or two beyond, depending on humidity. My cloth is fairly worn 760.

I hope you guys are all talking about shooting the 3-railer without side spin - otherwise who knows how much your aim depends on the amount of spin?

On my usual practice table (GC with clean, middle-aged 860) I aim without side spin just past the middle diamond between the side and corner pockets (on top of the rail).

pj
chgo

a proper 3 cushion shot would be with no english medium speed just above center ball.

hit the first diamond past the side pocket which is the third diamond up towards you from the back pocket. the cueball should then come off the third rail at the second diamond up and go into the pocket across from you every time without a miss..

when you start using running english on those shots that affects greatly and with your speed on where you have to hit to get it into the pocket. so then there is no way to use that as a guide on where to hit or how your rails play.

patrick
to keep inter player variation at a minimum vertical axis no spin results would be more uniform
most corner 5 billiard systems that i have seen in print use running english
(see pic below)
compensation for no spin is to aim 1/2 diamond less
from ceulemans Mr. 100 billiard book

 

[lll]

the above post has nothing to do with why diamonds play short.........:sorry
bottom line you have to adjust to the table you are on
if you have some key shots you hit with predictable results hit them on the table you are playing on and see how the results on TAHT table compare
thats how you can compensate
jmho

 

[Patrick Johnson]

The replies so far have been very interesting (thanks, everybody!), but I don't think they've answered the original question: WHY do Diamonds bank shorter?

My original theory remains: they bank shorter mostly because their rails are "faster" (balls rebound with greater speed). This means that (compared to slower rails) the perpendicular-to-the-rail component of their speed increases while the parallel-to-the-rail component is (mostly) unchanged, which makes their rebound angle "steeper".

Another factor may be different cushion nose heights, but I'm not sure how, in what direction, or how much effect that might have.

pj <- for what it's worth
chgo

 

[gulfportdoc]

PJ, your theory could be true. Has the ring of logic to it.

But this is not rocket science. I'm sure there's a very simple explanation (if it's different from yours). We might have to contact Greg Sullivan to find out. Perhaps Jewett knows?

~Doc

 

[Patrick Johnson]

PJ, your theory could be true. Has the ring of logic to it.

But this is not rocket science. I'm sure there's a very simple explanation (if it's different from yours). We might have to contact Greg Sullivan to find out. Perhaps Jewett knows?

~Doc

I notice Larry (lll) has posted the question on AzB (thanks Larry) - maybe we'll learn something new from that.

EDIT - First answer there:

"soft rubber -
acts like a catchers mit -
deeper into the rubber reduces the release angle -"

I don't buy it - seems to me softer rubber would allow the ball to travel farther along the rail before rebounding, widening the rebound angle. Another factor: softer rubber might rebound slower (not sure), also widening the rebound angle.

pj
chgo

 

[oldschool1478]

"soft rubber -
acts like a catchers mit -
deeper into the rubber reduces the release angle -"

I think the is true, and is the main reason all cushions bank shorter when hit hard.
Artemis cushions are softer than others, so the effect is increased.

The ball sinking into the cushion creates a temporary flatter effective angle.
I have seen this demonstrated in slow-mo somewhere on the net.

 

[Patrick Johnson]

"soft rubber -
acts like a catchers mit -
deeper into the rubber reduces the release angle -"

I think the is true, and is the main reason all cushions bank shorter when hit hard.
Artemis cushions are softer than others, so the effect is increased.

The ball sinking into the cushion creates a temporary flatter effective angle.
I have seen this demonstrated in slow-mo somewhere on the net.

I wish I could find the demonstration video by Bob Jewett and Dr. Dave showing that if you eliminate OB follow from the comparison the OB actually banks a little longer when hit harder - because digging deeper into the rail gives it a wider curved apex.

I think this suggests that softer banks go longer because of follow on the OB, and harder banks go shorter because they tend to slide into the rail with no follow.

In the end it probably doesn't matter what reason we believe, as long as it's consistent with what happens. I'm just a curious cat.

pj
chgo

 

[lll]

I notice Larry (lll) has posted the question on AzB (thanks Larry) - maybe we'll learn something new from that.

EDIT - First answer there:

"soft rubber -
acts like a catchers mit -
deeper into the rubber reduces the release angle -"

I don't buy it - seems to me softer rubber would allow the ball to travel farther along the rail before rebounding, widening the rebound angle. Another factor: softer rubber might rebound slower (not sure), also widening the rebound angle.

pj
chgo

I thought it would help get a few more opinions
But really
I am hoping realkingcobra will answer and not tease

 

[sausage]

What does it matter, they just do.

humans are a curious lot... this is what made us smart.

when i play on a table with "fast" rails, i always play my banks a little longer because I THINK that the ball sinks into the rail further causing it to shorten-up

 

[sausage]

because digging deeper into the rail gives it a wider curved apex.
chgo

i think that just the opposite is true. the more the ball sinks into the rail the shorter the bank. hence hitting banks hard shortens them up because there is now more cushion on the side of the ball.

 

[Patrick Johnson]

Here's what Mike Page, a retired science professor (and owner of Fargo Billiards and FargoRate), says on AzB.

pj
chgo

View attachment 68806

 

[lll]

this post from realkingcobra suggests its the angle of the nose of the cusion that was changed to make the blue labels bank closer to gold crowns
http://forums.azbilliards.com/showpost.php?p=3598967&postcount=23
mark gregory also commented on the difference between the artemis rails (on diamonds) and superspeed (on gold crowns)
http://forums.azbilliards.com/showpost.php?p=5790857&postcount=5
hope this helps